1. Field of the Invention
The present invention generally relates to optical switching components and, more particularly, to a compact wavelength routing device having a substantially flat passband.
2. Description of the Related Art
Optical wavelength division multiplexed (WDM) systems are becoming increasingly important. As the spectral efficiency of such WDM systems increases, wavelength routing devices that multiplex and demultiplex optical wavelengths require maximal passband width. A wider passband in the optical multiplexer/demultiplexer reduces the need for accurate control of the transmitted wavelengths and causes less signal distortion.
Presently, optical multiplexers and demultiplexers are realized in integrated form by using an imaging arrangement of waveguides having a constant path-length difference. Such devices are typically referred to as waveguide grating routers (WGRs). Attempts to increase or flatten the passband of WGRs have generally resulted in either lossy or large devices.
An optical apparatus comprising a first wavelength routing device having a first plurality of waveguide arms and a 180xc2x0 optical coupler, and a second wavelength routing device coupled to the first wavelength routing device, the second wavelength routing device having a second plurality of waveguide arms. Each of the second plurality of waveguide arms has a substantially opposite curvature relative to each of the first plurality of waveguide arms. In one embodiment, the first wavelength routing device is a Mach-Zehnder interferometer (MZI) having first and second waveguide arms, and the second wavelength routing devices is a waveguide grating router (WGR).
The present invention can be used to provide an optical multiplexer/demultiplexer having a substantially flat passband. In addition, the present invention is compact and stackable given the opposite curvature of the waveguide arms between the first wavelength routing device and the second wavelength routing device.